/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: Key.java,v 1.6 2006/04/25 02:25:08 jeffsuttor Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import java.util.Vector;

import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFEQ;
import com.sun.org.apache.bcel.internal.generic.IFGE;
import com.sun.org.apache.bcel.internal.generic.IFGT;
import com.sun.org.apache.bcel.internal.generic.ILOAD;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.ISTORE;
import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.StringType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
import com.sun.org.apache.xml.internal.dtm.Axis;
import com.sun.org.apache.xml.internal.utils.XML11Char;

/**
 * @author Morten Jorgensen
 * @author Santiago Pericas-Geertsen
 */
final class Key extends TopLevelElement {

  /**
   * The name of this key as defined in xsl:key.
   */
  private QName _name;

  /**
   * The pattern to match starting at the root node.
   */
  private Pattern _match;

  /**
   * The expression that generates the values for this key.
   */
  private Expression _use;

  /**
   * The type of the _use expression.
   */
  private Type _useType;

  /**
   * Parse the <xsl:key> element and attributes
   *
   * @param parser A reference to the stylesheet parser
   */
  public void parseContents(Parser parser) {

    // Get the required attributes and parser XPath expressions
    final String name = getAttribute("name");
    if (!XML11Char.isXML11ValidQName(name)) {
      ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, name, this);
      parser.reportError(Constants.ERROR, err);
    }

    // Parse key name and add to symbol table
    _name = parser.getQNameIgnoreDefaultNs(name);
    getSymbolTable().addKey(_name, this);

    _match = parser.parsePattern(this, "match", null);
    _use = parser.parseExpression(this, "use", null);

    // Make sure required attribute(s) have been set
    if (_name == null) {
      reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "name");
      return;
    }
    if (_match.isDummy()) {
      reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "match");
      return;
    }
    if (_use.isDummy()) {
      reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "use");
      return;
    }
  }

  /**
   * Returns a String-representation of this key's name
   *
   * @return The key's name (from the <xsl:key> elements 'name' attribute).
   */
  public String getName() {
    return _name.toString();
  }

  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    // Type check match pattern
    _match.typeCheck(stable);

    // Cast node values to string values (except for nodesets)
    _useType = _use.typeCheck(stable);
    if (_useType instanceof StringType == false &&
        _useType instanceof NodeSetType == false) {
      _use = new CastExpr(_use, Type.String);
    }

    return Type.Void;
  }

  /**
   * This method is called if the "use" attribute of the key contains a
   * node set. In this case we must traverse all nodes in the set and
   * create one entry in this key's index for each node in the set.
   */
  public void traverseNodeSet(ClassGenerator classGen,
      MethodGenerator methodGen,
      int buildKeyIndex) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    // DOM.getStringValueX(nodeIndex) => String
    final int getNodeValue = cpg.addInterfaceMethodref(DOM_INTF,
        GET_NODE_VALUE,
        "(I)" + STRING_SIG);

    final int getNodeIdent = cpg.addInterfaceMethodref(DOM_INTF,
        "getNodeIdent",
        "(I)" + NODE_SIG);

    // AbstractTranslet.SetKeyIndexDom(name, Dom) => void
    final int keyDom = cpg.addMethodref(TRANSLET_CLASS,
        "setKeyIndexDom",
        "(" + STRING_SIG + DOM_INTF_SIG + ")V");

    // This variable holds the id of the node we found with the "match"
    // attribute of xsl:key. This is the id we store, with the value we
    // get from the nodes we find here, in the index for this key.
    final LocalVariableGen parentNode =
        methodGen.addLocalVariable("parentNode",
            Util.getJCRefType("I"),
            null, null);

    // Get the 'parameter' from the stack and store it in a local var.
    parentNode.setStart(il.append(new ISTORE(parentNode.getIndex())));

    // Save current node and current iterator on the stack
    il.append(methodGen.loadCurrentNode());
    il.append(methodGen.loadIterator());

    // Overwrite current iterator with one that gives us only what we want
    _use.translate(classGen, methodGen);
    _use.startIterator(classGen, methodGen);
    il.append(methodGen.storeIterator());

    final BranchHandle nextNode = il.append(new GOTO(null));
    final InstructionHandle loop = il.append(NOP);

    // Prepare to call buildKeyIndex(String name, int node, String value);
    il.append(classGen.loadTranslet());
    il.append(new PUSH(cpg, _name.toString()));
    parentNode.setEnd(il.append(new ILOAD(parentNode.getIndex())));

    // Now get the node value and push it on the parameter stack
    il.append(methodGen.loadDOM());
    il.append(methodGen.loadCurrentNode());
    il.append(new INVOKEINTERFACE(getNodeValue, 2));

    // Finally do the call to add an entry in the index for this key.
    il.append(new INVOKEVIRTUAL(buildKeyIndex));

    il.append(classGen.loadTranslet());
    il.append(new PUSH(cpg, getName()));
    il.append(methodGen.loadDOM());
    il.append(new INVOKEVIRTUAL(keyDom));

    nextNode.setTarget(il.append(methodGen.loadIterator()));
    il.append(methodGen.nextNode());

    il.append(DUP);
    il.append(methodGen.storeCurrentNode());
    il.append(new IFGE(loop)); // Go on to next matching node....

    // Restore current node and current iterator from the stack
    il.append(methodGen.storeIterator());
    il.append(methodGen.storeCurrentNode());
  }

  /**
   * Gather all nodes that match the expression in the attribute "match"
   * and add one (or more) entries in this key's index.
   */
  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();
    final int current = methodGen.getLocalIndex("current");

    // AbstractTranslet.buildKeyIndex(name,node_id,value) => void
    final int key = cpg.addMethodref(TRANSLET_CLASS,
        "buildKeyIndex",
        "(" + STRING_SIG + "I" + OBJECT_SIG + ")V");

    // AbstractTranslet.SetKeyIndexDom(name, Dom) => void
    final int keyDom = cpg.addMethodref(TRANSLET_CLASS,
        "setKeyIndexDom",
        "(" + STRING_SIG + DOM_INTF_SIG + ")V");

    final int getNodeIdent = cpg.addInterfaceMethodref(DOM_INTF,
        "getNodeIdent",
        "(I)" + NODE_SIG);

    // DOM.getAxisIterator(root) => NodeIterator
    final int git = cpg.addInterfaceMethodref(DOM_INTF,
        "getAxisIterator",
        "(I)" + NODE_ITERATOR_SIG);

    il.append(methodGen.loadCurrentNode());
    il.append(methodGen.loadIterator());

    // Get an iterator for all nodes in the DOM
    il.append(methodGen.loadDOM());
    il.append(new PUSH(cpg, Axis.DESCENDANT));
    il.append(new INVOKEINTERFACE(git, 2));

    // Reset the iterator to start with the root node
    il.append(methodGen.loadCurrentNode());
    il.append(methodGen.setStartNode());
    il.append(methodGen.storeIterator());

    // Loop for traversing all nodes in the DOM
    final BranchHandle nextNode = il.append(new GOTO(null));
    final InstructionHandle loop = il.append(NOP);

    // Check if the current node matches the pattern in "match"
    il.append(methodGen.loadCurrentNode());
    _match.translate(classGen, methodGen);
    _match.synthesize(classGen, methodGen); // Leaves 0 or 1 on stack
    final BranchHandle skipNode = il.append(new IFEQ(null));

    // If this is a node-set we must go through each node in the set
    if (_useType instanceof NodeSetType) {
      // Pass current node as parameter (we're indexing on that node)
      il.append(methodGen.loadCurrentNode());
      traverseNodeSet(classGen, methodGen, key);
    } else {
      il.append(classGen.loadTranslet());
      il.append(DUP);
      il.append(new PUSH(cpg, _name.toString()));
      il.append(DUP_X1);
      il.append(methodGen.loadCurrentNode());
      _use.translate(classGen, methodGen);
      il.append(new INVOKEVIRTUAL(key));

      il.append(methodGen.loadDOM());
      il.append(new INVOKEVIRTUAL(keyDom));
    }

    // Get the next node from the iterator and do loop again...
    final InstructionHandle skip = il.append(NOP);

    il.append(methodGen.loadIterator());
    il.append(methodGen.nextNode());
    il.append(DUP);
    il.append(methodGen.storeCurrentNode());
    il.append(new IFGT(loop));

    // Restore current node and current iterator from the stack
    il.append(methodGen.storeIterator());
    il.append(methodGen.storeCurrentNode());

    nextNode.setTarget(skip);
    skipNode.setTarget(skip);
  }
}
